Posted on November 01 2017


Thomas Grimmett


Product News, Video

Glass Blowing Tutorial: Understanding Your Kiln


What’s up guys, Thomas here.  I make the color at Glass Alchemy.

Today we’re going to be talking about your kiln and how to make sure it’s working for you.

I’ve got a couple kilns going right now and I want to show you how different a kiln can be from another kiln depending on the manufacturer and model number.  

Some kilns have their elements in the side walls, some kilns have their elements in the roof.  Some thermocouples, which is what reads the temperature in the kiln, are located closer to the floor, as is the case here.  There is a thermocouple all the way in the left there towards the bottom.  And in this kiln here, you will notice the thermocouple is closer to the roof.

What I want to show you is how the different models work, but also do a demonstration to show you how you can do your own calibration of your kiln and get the best results with your annealing schedules.

For this example, I have a rod of un-struck Half Blood, 1933.  I am going to place the four different sections of the rod into four different places in the kiln.  Then we will check on it after 20 minutes at 1075 and we are going to see if the rods are all striking red the way they are supposed to.

I’ve got the four different section of the rod in four different locations.  One is over to the left by the thermocouple sensor.  Another one is on the right wall, furthest from the thermocouple sensor.  There is a rod laying down in the back of the kiln, and there is a rod laying down in the front of the kiln.

We are going to let these go for about 20 minutes at 1075, then we will check in on them.

Here we are after about 20 minutes.  You can see the glass leaning on the side wall towards the top has stuck a nice and deep red, but towards the floor we haven’t seen much color change.  At the back of the kiln, we have a rod laying flat that struck all the same color and the rod towards the front is only partially struck.

So, if you are leaving your work towards the door in the kiln, you can see what’s happening with your heat base.   Typically, stuff that’s on the ground versus higher up tends to not be at the same temperature as the rest of the kiln. 


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